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MIDI TO SYNC INTERFACE 

MSY2 

User's Guide (English) 




www.doepfer.com 



INTRODUCTION 

MSY2 is an interface that converts the MIDI realtime events CLOCK, START and STOP into the 
corresponding signals CLOCK and START/STOP of the SYNC standard. The SYNC standard is 
used in vintage drum computers or sequencers such as the Roland TR808 rhythm composer or 
the TB303 bass line. SYNC-CLOCK is a periodic TTL signal (0/+5V) representing the tempo. 
SYNC-START/STOP is a signal that indicates on the 2 possible states: START = +5V, STOP = 
OV. MSY2 enables the 1 :1 conversion of MIDI CLOCK to SYNC CLOCK i.e. 1 MIDI clock triggers 1 
SYNC clock pulse, as well as the reduction of the tempo by dividing the incoming MIDI clock 
frequency by an integer factor. The factor can be set to any value between 1 and 16 with 4 DIP 
switches. 1 corresponds to the 1:1 conversion, 16 is the maximum of frequency reduction, i.e. after 
16 MIDI clocks 1 SYNC clock appears. The polarity of the CLOCK signal and the polarity of the 
START/STOP can be chosen by 2 DIP switches. 

The SYNC standard is used with vintage sequencers or drum computers like the ROLAND TB303 
orTR808. The SYNC standard uses the same type of 5 pole 180° DIN connectors as MIDI. But the 
standards do not fit as other pins are used and the signals are completely different! So you always 
have to distinguish between the MIDI and SYNC connectors. 




Clock (J3 1(J Start/Stop 



Gnd 
Picture 1: pinout of the SYNC connector 



CONNECTIONS 

MSY2 is provided with 2 SYNC connectors (parallel) for controlling 1 or 2 units equipped with 
SYNC inputs. The CLOCK signal is additionally available at a 3.5mm miniature jack socket to 
control other functions of synthesizers or drum machines like arpeggio, gate or trigger 
synchronized ti MIDI Clock. At the Clock socket appears the Clock signal of the SYNC connector 
i.e. with the same dividing factor and voltage level. 

Connect MIDI IN of the MSY2 to MIDI OUT of the MIDI transmitter (e.g. MIDI sequencer, MIDI 
drum computer, MIDI master-keyboard) which is able to generate the MIDI real time events Start, 
Stop and Clock. The MIDI THRU of the MSY2 may be connected to MIDI IN of other MIDI devices 
(optional). 

Connect one of the SYNC outputs of the MSY2 to the SYNC (-In) socket of the device to be 
controlled by the MSY2. The second SYNC ouput may be left open or connected to another device 
controlled by the MSY2 SYNC output. Use a suitable cable for that. The pins 1 , 2 and 3 must be 
connected! MIDI cables are unsuitable! If the SYNC socket of your device can be switched 
between SYNC-IN and SYNC-OUT switch it to SYNC-IN (e.g. TR808). If your device is equipped 
with SYNC-IN and SYNC-OUT use only SYNC-IN. 



MSY2 User's Guide - Page 1 



If desired you may connect the Clock output jack to the control input of another device (e.g. the 
arpeggiator control input of a synthesizer or a drum machin with separate Clock input) to control it 
with a MIDI synchronized Clock signal. Use a suitable cable. Normally a cable with a 1/4" mono 
jack plug on one side (device) and a 3.5mm miniatur mono jack plug (MSY2) on the other side will 
be used. 



POWER SUPPLY 

MSY2 does not have a built-in power supply. It can be supplied in two different ways: 

• power supply via MIDI In 

• power supply via external AC adapter 

We recommend the power supply with an external AC adapter as this type of power supply will 
work under all circumstances. So the factory setting of the power select jumper (see below) is for 
external AC adapter. 

If you want to supply the MSY2 via MIDI In the MIDI transmitter must correspond 100% to the MIDI 
standard, i.e. pin 4 of MIDI out must be connected to +5V via a resistor of 220Q and pin 2 must be 
connected to Gnd. We found that some MIDI devices do not comply with this demand. 

To check whether your MIDI transmitter is suitable for this type of power supply you have to do the 
following: Open the case of the MSY2 by removing the 4 screws using a suitable tool. Inside you 
see the pc board of the MSY2 with 2 possible jumper locations: 




jumper for power 
supply via AC adapter 



jumper for power 
supply via MIDI In 




MSY2 version 1 



MSY2 version 2 



Picture 2: jumper location for power supply selection 



One of the jumpers is located near the power supply connector. If this jumper is set the MSY2 is 
supplied from an external AC adapter (7. ..12V, 100mA minimum). This is the factory setting. If the 
jumper near the MIDI-ln socket is set the MSY2 is supplied from MIDI (if the MIDI transmitter used 
is 100% MIDI compatible). 

Only one of the two jumpers is allowed to be set. Otherwise the MSY2 will be damaged! If none of 
the two jumpers is set the MSY2 will not work. 

When connecting the MSY2 to MIDI Out of the controlliung device the Clock LED must light up and 
remain on until the first MIDI clock event occurs. If this happens the power supply viy MIDI is 
possible. Otherwise the MSY2 must be supplied from an external AC adapter. 



MSY2 User's Guide - Page 2 



Pay attention if you open and close the MSY2 case. Use only a suitable screw driver. We cannot 
take back units if the case or LEDs are damaged and the warranty will be lost during such 
manipulations. If you are not sure whether your are able to do the modification send the unit to 
your local dealer or to Doepfer Musikelektronik, Graefelfing (Germany). 

The external power supply (AC adapter) is NOT included with the MSY2 and must be purchased 
locally by the user. We recommend an VDE approved AC adapter but MSY2 will work with every 
AC adapter being in accordance with the following specifications. The adapter must be able to 
deliver 7-12 V DC unstabilized or stabilized voltage, as well as a minimum current of 100 mA. The 
POLARITY of the low voltage plug connected to the MSY2 must be pin = +7...12V and ring = GND 
(see sketch on the MSY2 housing). If the polarity is incorrect, MSY2 will not function. However, 
there is no danger of damage to the circuitry since it is protected by a diode. If the MSY2 is used in 
Germany the external power supply must be VDE approved. 

When using an external power supply the MSY2 is SWITCHED ON by plugging the AC adapter 
into a wall outlet and connecting it to the jack labeled "9V DC" of the MSY1 . There is no separate 
ON/OFF switch. 



OPERATION 

After power on (vie external AC adapter or MIDI In) the Clock LED must light up and remain on 
until the first MIDI clock event occurs. During this period the Clock LED works as a power indicator. 
If the Clock LED does not light up the AC adapter used is not suitable or does not work (or the 
power supply via MIDI In is not possible, see preceding chapter) or the MIDI transmitter is already 
sending MIDI Clock events. In the last cast you should set the MIDI transmitter to Stop mode 
(normally by pressing a Stop button). Most MIDI devices stop transmission of MIDI Clock events 
during stop mode. 

In case of an incoming MIDI START event (normally followed by MIDI CLOCK signals) the START 
LED will light up and the CLOCK LED will flash indicating the tempo. Because of the inertia of the 
eye higher frequencies are not perceptible. 

In case of an incoming MIDI STOP event the Start/Stop LED turns off and normally the Clock LED 
as well as most of the MIDI devices stop the transmission of Clock events in Stop mode. In case 
that the MIDI transmitter is sending Clock events in the stop mode too the Clock LED will continue 
flashing. 

If one of the two SYNC outputs of the MSY2 is connected faultless to your device equipped with a 
SYNC input socket it should respond to the MIDI events, i.e. start, stop and change the tempo via 
MIDI. If the two LEDs of the MSY2 display properly but your device does not respond there is 
probably a fault in the connection between MSY2 and your device (unsuitable cable) or the SYNC 
input of your device is not switched to SYNC-ln or the SYNC input is not in accordance with the 
SYNC standard. 

If you want to slow down the SYNC clock frequency you may change the CLOCK DIVIDING 
FACTOR. The factory setting is 1 :1 conversion, i.e. each MIDI Clock trigger a SYNC Clock pulse. 
To change the dividing factor you have change the setting of the first 4 DIP switches located at the 
bottom of the MSY2 case. The dividing factor can be set between 1 and 16. The valences of the 4 
DIP switches are 8, 4, 2, 1 (from left to right, see pictures 3 and 4). 



MSY2 User's Guide - Page 3 



DIP switch 


Valence "off" 


Valence "on" 


1 


8 





2 


4 





3 


2 





4 


1 






Picture 3: Valences of DIP switches for Clock dividing factor 

The valence of the switches increase in the 2's power rule (1, 2, 4, 8). To obtain the resulting 
dividing factor you have to add 1 to the calculated value from the table above. 

Example: To obtain a dividing factor of 6 you have set the switches 2 and 4 to "off" and the 
switches 1 and 3 to "on". This results in the valences 0+4+0+1 = 5. If you add 1 you get the 
resulting factor 6. 

Normally you will not have to calculate the dividing factor rather you try some switch settings to find 
the desired SYNC clock divider. As a rule only the lower factors (1:1 ... 1 :6) are making sense. You 
should start with the maximum Clock (i.e. dividing factor 1) and increase the dividing factor if the 
device controlled by the MSY2 is running too fast. Pay attention that some of the devices to be 
controlled by MSY2 additionally enable to change the dividing factor inside the device (e.g. TR808: 
"prescale"). Devices with a SYNC socket normally can be driven with the maximum speed (i.e. 
dividing factor 1) 

The MIDI Clock is defined as 96 beats per measure. To obtain an even SYNC Clock like 32, 16 or 
8 beats per measure the dividing factor must be a multiple of 3 (e.g. 96/3 = 32, 96/6 = 16, 96/12 = 
8). Especially for non-SYNC applications (e.g. arpeggio of a synthesizer) you will need such even 
Clocks. 



Clock 
dividinc 

factor 




J Cluck 
polarity 


'8 4 2 


1 | — Start/Stop 




polarity 


12 3 4 5 6 



Picture 4: Location and function of the DIP switches at the bottom 

The last 2 switches correspond to the polarity of Clock and Start/Stop. Normally both switches are 
set to "on" as this is the standard for SYNC applications (factory setting). The Clock polarity switch 
determines whether the falling or rising edge appears on the SYNC clock output when a MIDI clock 
is received. Normally this setting is of no account as the clock pulse width (i.e. the time difference 
between the falling and rising edge) is very small (about 4 milliseconds in the 1 :1 setting). If you 
have the impression that there is a small time difference between your device and MIDI clock you 
may change the setting of the clock polarity. The Start/Stop polarity switch is used only for special 
applications (e.g. for drum computers with inverse Start/Stop control: 0V=Start, +5V=Stop). 



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